A) Field of the Invention
The present invention relates to a clutch cover assembly for engaging and disengaging a clutch disk from a flywheel. More specifically, the present invention relates to a clutch cover having a wear adjustment with spring biased wedge elements.
B) Description of the Related Art
A clutch cover assembly is normally mounted on the flywheel of an engine, grips a clutch disk between itself and the flywheel and serves to transmit an engines drive power to a speed-change gear. It is desirable for such a clutch cover assembly and clutch disk to have a long-life. Attempts have therefore been made to increase the effective useful thickness of clutch disk friction facings by fixing them to a cushioning plate without using rivets, etc, to extend clutch life.
There has also been proposed a clutch cover assembly structure which, as described in the disclosure of Japanese Laid-open Patent Application No. 63-27092, is designed to make it possible for the biasing load of a diaphragm spring to be automatically restored to its initial load strength when the facings become worn. This clutch cover assembly includes fulcrum rings or support elements that are located between the diaphragm spring and the pressure plate and are for the purpose of supporting the diaphragm spring. In this design, a wear compensation mechanism urges the diaphragm spring in a direction extending away from the pressure plate.
The wear compensation mechanism includes slide elements that are located in a groove of the pressure plate and are movable circumferentially and coil springs that urge these slide elements in the circumferential direction. The fulcrum springs and the slide elements have mutually contacting wedge surfaces, and when, after facing wear has occurred, pushing pressure on the diaphragm spring is released, the slide elements push the fulcrum springs in the circumferential direction, and the fulcrum springs move towards the diaphragm spring biasing section side. As a result, the diaphragm spring's biasing attitude does not change, and its setting load is maintained at the initial load.
In the above conventional structure, the coil springs are installed in a compressed state between the slide elements and the pressure plate support section. In order to install the coil springs in this location, the coil springs are assembled in set positions, and then, while the coil springs are kept compressed, the slide elements are set in place. It sometimes happens that, when the coil springs are compressed, they become bent and so fail to be installed in a correct attitude. When the coil springs' attitudes are incorrect, changes in the urging force exerted on the fulcrum rings occur.
Also, the efficiency of assembly work is poor, since the above installation work has to be done while the resilient force of the coil springs is acting. As a result, assembly takes a long time.
Further, the resilient force of the coil springs acts to move the fulcrum springs away from the pressure plate after they have been set in place. Suppressing this movement necessitates the use of special jigs and makes work troublesome.